1. Material problems of SMLS tubes
Many companies use more materials, usually nickel content. Although it can be used to distinguish drugs, it is clearly a misunderstanding, because a small amount of charge with less than 7 nickel content cannot be distinguished. But the price difference between raw materials is very large, which is one of the fakes.  Especially 321 high nickel and 316 high nickel counterfeits are very serious.
 
2. Size of SMLS tubes
Many customers have little technical support for testing. For example, for 90 degree elbow, the conventional R = 1.5D, but look at the Wenzhou market die production is basically more than 1.25D, do not underestimate the weight of 0.25D This is the so-called factory standard, which is much shorter than the standard.
 
3. Thickness of SMLS tubes
Of course, now customers are very smart, will use thickness to measure thickness, although sometimes customers feel reluctant to comply with the rules, but the neglect is that the thickness of the back arc is not enough! Because the elbow drive process will be reduced, the caliber is barely compliant.
 
4. Nondestructive Testing of Sand Dissolution and Sand and Sand Processing and Sand Blasting of Smls Pipe
Many manufacturers in the market do not carry out solid solution treatment and 100% penetration nondestructive testing, and there are many sand blasting instead of sand blasting, which saves these steps and greatly reduces costs.
 
5. Seamless welding
Welding seamless is to make welding elbow. After sandblasting, grinding and pickling, there is no sign of welding on the surface. Even using advanced testing equipment, it can not be seen that it is a welding elbow.
 
6. Spot welding, repair welding
Elbow drive process will become thinner, so in general, manufacturers will use thicker pipelines. If you use thin raw materials, they are definitely not qualified. Generally, about 40 wire thinning, such as poor technology or the use of pull pipe, the thickness is much lower than the standard.